Conventionally, in cataract surgery in which a clouded crystalline lens in the eye is replaced with an artificial intraocular lens, in order to make the incision smaller, a method of inserting the intraocular lens into the eye in a folded state has been known. An injector for an intraocular lens is used in the operation to fold and insert this intraocular lens into the eye. There is Patent Document 1 as an example disclosing this type of injector for an intraocular lens. Patent Document 1 discloses the following configuration for an intraocular lens insertion instrument for inserting an intraocular lens into the eye. In other words, the intraocular lens insertion instrument includes: an outer cylinder including an insertion part that inserts into an incision formed in the eyeball; a push-out means for pushing out the intraocular lens housed inside the outer cylinder to be able to advance/retract through an insertion part into the eye; a friction producing member that is placed so as to contact the push-out means, and producing a frictional force on the push-out device; and an adjustment member that is installed inside the outer cylinder, pressurizes the friction producing member from the axial direction of the push-out means, and adjusts a force pushing out according to a change in rotation angle relative to the axial direction of the push-out means.    Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2004-173805